Typo3DatabaseBackend.php

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<?php
namespace TYPO3\CMS\Core\Cache\Backend;

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */
use TYPO3\CMS\Core\Cache\Exception;
use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
use TYPO3\CMS\Core\Utility\ExtensionManagementUtility;

class Typo3DatabaseBackend extends AbstractBackend implements TaggableBackendInterface
{
    const FAKED_UNLIMITED_EXPIRE = 2145909600;
    protected $cacheTable;

    protected $tagsTable;

    protected $compression = false;

    protected $compressionLevel = -1;

    protected $identifierField;

    protected $expiresField;

    protected $maximumLifetime;

    protected $notExpiredStatement;

    protected $expiredStatement;

    protected $tableList;

    protected $tableJoin;

    public function setCache(FrontendInterface $cache)
    {
        parent::setCache($cache);
        $this->cacheTable = 'cf_' . $this->cacheIdentifier;
        $this->tagsTable = 'cf_' . $this->cacheIdentifier . '_tags';
        $this->initializeCommonReferences();
    }

    protected function initializeCommonReferences()
    {
        $this->identifierField = $this->cacheTable . '.identifier';
        $this->expiresField = $this->cacheTable . '.expires';
        $this->maximumLifetime = self::FAKED_UNLIMITED_EXPIRE - $GLOBALS['EXEC_TIME'];
        $this->tableList = $this->cacheTable . ', ' . $this->tagsTable;
        $this->tableJoin = $this->identifierField . ' = ' . $this->tagsTable . '.identifier';
        $this->expiredStatement = $this->expiresField . ' < ' . $GLOBALS['EXEC_TIME'];
        $this->notExpiredStatement = $this->expiresField . ' >= ' . $GLOBALS['EXEC_TIME'];
    }

    public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
    {
        $this->throwExceptionIfFrontendDoesNotExist();
        if (!is_string($data)) {
            throw new Exception\InvalidDataException(
                'The specified data is of type "' . gettype($data) . '" but a string is expected.',
                1236518298
            );
        }
        if (is_null($lifetime)) {
            $lifetime = $this->defaultLifetime;
        }
        if ($lifetime === 0 || $lifetime > $this->maximumLifetime) {
            $lifetime = $this->maximumLifetime;
        }
        $expires = $GLOBALS['EXEC_TIME'] + $lifetime;
        $this->remove($entryIdentifier);
        if ($this->compression) {
            $data = gzcompress($data, $this->compressionLevel);
        }
        $GLOBALS['TYPO3_DB']->exec_INSERTquery($this->cacheTable, [
            'identifier' => $entryIdentifier,
            'expires' => $expires,
            'content' => $data
        ]);
        if (!empty($tags)) {
            $fields = [];
            $fields[] = 'identifier';
            $fields[] = 'tag';
            $tagRows = [];
            foreach ($tags as $tag) {
                $tagRow = [];
                $tagRow[] = $entryIdentifier;
                $tagRow[] = $tag;
                $tagRows[] = $tagRow;
            }
            $GLOBALS['TYPO3_DB']->exec_INSERTmultipleRows($this->tagsTable, $fields, $tagRows);
        }
    }

    public function get($entryIdentifier)
    {
        $this->throwExceptionIfFrontendDoesNotExist();

        $cacheEntry = $GLOBALS['TYPO3_DB']->exec_SELECTgetSingleRow(
            'content',
            $this->cacheTable,
            'identifier = ' . $GLOBALS['TYPO3_DB']->fullQuoteStr($entryIdentifier, $this->cacheTable) . ' AND ' . $this->notExpiredStatement
        );
        if (is_array($cacheEntry)) {
            $cacheEntry = $cacheEntry['content'];
        }
        if ($this->compression && (string)$cacheEntry !== '') {
            $cacheEntry = gzuncompress($cacheEntry);
        }
        return $cacheEntry !== null ? $cacheEntry : false;
    }

    public function has($entryIdentifier)
    {
        $this->throwExceptionIfFrontendDoesNotExist();
        $hasEntry = false;
        $cacheEntries = $GLOBALS['TYPO3_DB']->exec_SELECTcountRows(
            '*',
            $this->cacheTable,
            'identifier = ' . $GLOBALS['TYPO3_DB']->fullQuoteStr($entryIdentifier, $this->cacheTable) . ' AND ' . $this->notExpiredStatement
        );
        if ($cacheEntries >= 1) {
            $hasEntry = true;
        }
        return $hasEntry;
    }

    public function remove($entryIdentifier)
    {
        $this->throwExceptionIfFrontendDoesNotExist();
        $entryRemoved = false;
        $GLOBALS['TYPO3_DB']->exec_DELETEquery(
            $this->cacheTable,
            'identifier = ' . $GLOBALS['TYPO3_DB']->fullQuoteStr($entryIdentifier, $this->cacheTable)
        );
        // we need to save the affected rows as mysqli_affected_rows just returns the amount of affected rows
        // of the last call
        $affectedRows = $GLOBALS['TYPO3_DB']->sql_affected_rows();
        $GLOBALS['TYPO3_DB']->exec_DELETEquery(
            $this->tagsTable,
            'identifier = ' . $GLOBALS['TYPO3_DB']->fullQuoteStr($entryIdentifier, $this->tagsTable)
        );
        if ($affectedRows == 1) {
            $entryRemoved = true;
        }
        return $entryRemoved;
    }

    public function findIdentifiersByTag($tag)
    {
        $this->throwExceptionIfFrontendDoesNotExist();
        $cacheEntryIdentifiers = [];
        $cacheEntryIdentifierRows = $GLOBALS['TYPO3_DB']->exec_SELECTgetRows(
            $this->identifierField,
            $this->tableList,
            $this->tagsTable . '.tag = ' . $GLOBALS['TYPO3_DB']->fullQuoteStr($tag, $this->tagsTable) . ' AND ' . $this->tableJoin . ' AND ' . $this->notExpiredStatement,
            $this->identifierField
        );
        foreach ($cacheEntryIdentifierRows as $cacheEntryIdentifierRow) {
            $cacheEntryIdentifiers[$cacheEntryIdentifierRow['identifier']] = $cacheEntryIdentifierRow['identifier'];
        }
        return $cacheEntryIdentifiers;
    }

    public function flush()
    {
        $this->throwExceptionIfFrontendDoesNotExist();
        $GLOBALS['TYPO3_DB']->exec_TRUNCATEquery($this->cacheTable);
        $GLOBALS['TYPO3_DB']->exec_TRUNCATEquery($this->tagsTable);
    }

    public function flushByTag($tag)
    {
        $this->throwExceptionIfFrontendDoesNotExist();

        if ($this->isConnectionMysql()) {
            $GLOBALS['TYPO3_DB']->sql_query('
                DELETE tags2, cache1'
                . ' FROM ' . $this->tagsTable . ' AS tags1'
                . ' JOIN ' . $this->tagsTable . ' AS tags2 ON tags1.identifier = tags2.identifier'
                . ' JOIN ' . $this->cacheTable . ' AS cache1 ON tags1.identifier = cache1.identifier'
                . ' WHERE tags1.tag = ' . $GLOBALS['TYPO3_DB']->fullQuoteStr($tag, $this->tagsTable)
            );
        } else {
            $tagsTableWhereClause = $this->tagsTable . '.tag = ' . $GLOBALS['TYPO3_DB']->fullQuoteStr($tag, $this->tagsTable);
            $cacheEntryIdentifierRowsResource = $GLOBALS['TYPO3_DB']->exec_SELECTquery('DISTINCT identifier', $this->tagsTable, $tagsTableWhereClause);
            $cacheEntryIdentifiers = [];
            while ($cacheEntryIdentifierRow = $GLOBALS['TYPO3_DB']->sql_fetch_assoc($cacheEntryIdentifierRowsResource)) {
                $cacheEntryIdentifiers[] = $GLOBALS['TYPO3_DB']->fullQuoteStr($cacheEntryIdentifierRow['identifier'], $this->cacheTable);
            }
            $GLOBALS['TYPO3_DB']->sql_free_result($cacheEntryIdentifierRowsResource);
            if (!empty($cacheEntryIdentifiers)) {
                $deleteWhereClause = 'identifier IN (' . implode(', ', $cacheEntryIdentifiers) . ')';
                $GLOBALS['TYPO3_DB']->exec_DELETEquery($this->cacheTable, $deleteWhereClause);
                $GLOBALS['TYPO3_DB']->exec_DELETEquery($this->tagsTable, $deleteWhereClause);
            }
        }
    }

    public function collectGarbage()
    {
        $this->throwExceptionIfFrontendDoesNotExist();

        if ($this->isConnectionMysql()) {
            // First delete all expired rows from cache table and their connected tag rows
            $GLOBALS['TYPO3_DB']->sql_query(
                'DELETE cache, tags'
                . ' FROM ' . $this->cacheTable . ' AS cache'
                . ' LEFT OUTER JOIN ' . $this->tagsTable . ' AS tags ON cache.identifier = tags.identifier'
                . ' WHERE cache.expires < ' . $GLOBALS['EXEC_TIME']
            );
            // Then delete possible "orphaned" rows from tags table - tags that have no cache row for whatever reason
            $GLOBALS['TYPO3_DB']->sql_query(
                'DELETE tags'
                . ' FROM ' . $this->tagsTable . ' AS tags'
                . ' LEFT OUTER JOIN ' . $this->cacheTable . ' AS cache ON tags.identifier = cache.identifier'
                . ' WHERE cache.identifier IS NULL'
            );
        } else {
            // Get identifiers of expired cache entries
            $cacheEntryIdentifierRowsResource = $GLOBALS['TYPO3_DB']->exec_SELECTquery('DISTINCT identifier', $this->cacheTable, 'expires < ' . $GLOBALS['EXEC_TIME']);
            $cacheEntryIdentifiers = [];
            while ($cacheEntryIdentifierRow = $GLOBALS['TYPO3_DB']->sql_fetch_assoc($cacheEntryIdentifierRowsResource)) {
                $cacheEntryIdentifiers[] = $GLOBALS['TYPO3_DB']->fullQuoteStr($cacheEntryIdentifierRow['identifier'], $this->tagsTable);
            }
            $GLOBALS['TYPO3_DB']->sql_free_result($cacheEntryIdentifierRowsResource);
            // Delete tag rows connected to expired cache entries
            if (!empty($cacheEntryIdentifiers)) {
                $GLOBALS['TYPO3_DB']->exec_DELETEquery($this->tagsTable, 'identifier IN (' . implode(', ', $cacheEntryIdentifiers) . ')');
            }
            // Delete expired cache rows
            $GLOBALS['TYPO3_DB']->exec_DELETEquery($this->cacheTable, 'expires < ' . $GLOBALS['EXEC_TIME']);

            // Find out which "orphaned" tags rows exists that have no cache row and delete those, too.
            $result = $GLOBALS['TYPO3_DB']->sql_query(
                'SELECT tags.identifier'
                . ' FROM ' . $this->tagsTable . ' AS tags'
                . ' LEFT OUTER JOIN ' . $this->cacheTable . ' AS cache ON tags.identifier = cache.identifier'
                . ' WHERE cache.identifier IS NULL'
                . ' GROUP BY tags.identifier'
            );

            while ($row = $GLOBALS['TYPO3_DB']->sql_fetch_assoc($result)) {
                $tagsEntryIdentifiers[] = $GLOBALS['TYPO3_DB']->fullQuoteStr($row['identifier'], $this->tagsTable);
            }

            if (!empty($tagsEntryIdentifiers)) {
                $GLOBALS['TYPO3_DB']->sql_query(
                    'DELETE'
                    . ' FROM ' . $this->tagsTable
                    . ' WHERE identifier IN (' . implode(',', $tagsEntryIdentifiers) . ')'
                );
            }
        }
    }

    public function getCacheTable()
    {
        $this->throwExceptionIfFrontendDoesNotExist();
        return $this->cacheTable;
    }

    public function getTagsTable()
    {
        $this->throwExceptionIfFrontendDoesNotExist();
        return $this->tagsTable;
    }

    public function setCompression($compression)
    {
        $this->compression = $compression;
    }

    public function setCompressionLevel($compressionLevel)
    {
        if ($compressionLevel >= -1 && $compressionLevel <= 9) {
            $this->compressionLevel = $compressionLevel;
        }
    }

    protected function throwExceptionIfFrontendDoesNotExist()
    {
        if (!$this->cache instanceof FrontendInterface) {
            throw new Exception('No cache frontend has been set via setCache() yet.', 1236518288);
        }
    }

    public function getTableDefinitions()
    {
        $cacheTableSql = file_get_contents(
            ExtensionManagementUtility::extPath('core') .
            'Resources/Private/Sql/Cache/Backend/Typo3DatabaseBackendCache.sql'
        );
        $requiredTableStructures = str_replace('###CACHE_TABLE###', $this->cacheTable, $cacheTableSql) . LF . LF;
        $tagsTableSql = file_get_contents(
            ExtensionManagementUtility::extPath('core') .
            'Resources/Private/Sql/Cache/Backend/Typo3DatabaseBackendTags.sql'
        );
        $requiredTableStructures .= str_replace('###TAGS_TABLE###', $this->tagsTable, $tagsTableSql) . LF;
        return $requiredTableStructures;
    }

    protected function isConnectionMysql()
    {
        return !((bool)ExtensionManagementUtility::isLoaded('dbal'));
    }
}